SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549



In the Matter of:                                 QUARTERLY CERTIFICATE
                                                  PURSUANT TO RULE 24 UNDER THE
AMEREN CORPORATION,                               PUBLIC UTILITY HOLDING COMPANY
         and its Subsidiaries                     ACT OF 1935



File Nos.  70-9877, 70-10078, 70-10106, 70-9427


================================================================================

     Ameren Corporation  ("Ameren"),  a registered holding company, on behalf of
itself and its subsidiaries,  hereby files this certificate  pursuant to Rule 24
reporting on  transactions  authorized by the Commission by orders dated October
5, 2001 (Holding Co. Act Release No. 27449),  February 27, 2003 (Holding Co. Act
Release No. 27655),  January 29, 2003 (Holding Co. Act Release No.  27645),  and
July 23, 1999 (Holding Co. Act Release No.  27053).  This  certificate  is filed
with respect to transactions consummated during the quarter ended June 30, 2003.

A.   Financing by Ameren (File No. 70-9877):
     -------------------

     1.   Sales of any Common  Stock by Ameren  (other  than  pursuant  to Stock
          Plans) and the purchase price per share and the market price per share
          at the date of the agreement of sale.

     No such sales occurred during the 2nd quarter of 2003.


     2.   The total number of shares of Common  Stock  issued or issuable  under
          options,  warrants or other  stock-purchase  rights granted during the
          quarter under Stock Plans.

          Dividend Reinvestment and Stock Purchase Plan:         429,690
          Long Term Savings Plan 148 CIPS:                         6,714
          Long Term Savings Plan 702 CIPS:                        10,386
          Long Term Savings Plan CILCO                            13,125
          Savings Investment Plan Ameren                          99,055
          Long Term Incentive Plan (Restricted Common Stock)           0

              Total                                              558,970


     3.   If Common Stock has been  transferred  to a seller of  securities of a
          company being acquired,  the number of shares so issued, the value per
          share and whether the shares are restricted to the acquiror.

          N/A


     4.   The amount and terms of any Long-term  Debt,  Preferred Stock or other
          preferred or equity-linked  securities  issued by Ameren,  directly or
          indirectly  through  a  Financing  Subsidiary,   during  the  calendar
          quarter.

          No such securities were issued during the 2nd quarter of 2003.




     5.   The  amount  and  terms of any  Short-term  Debt  issued  directly  or
          indirectly by Ameren during the calendar quarter.

          A.   There was no  commercial  paper issued  during the 2nd quarter of
               2003.
          B.   There were no bank loans for the 2nd quarter of 2003.

          Maximum indebtedness at any one time:  $0.


     6.   A description of the amount, terms and purpose of any Guarantee issued
          during the calendar  quarter by Ameren and the name of the beneficiary
          of such Guarantee.




          Parent              Subsidiary                                Amount              Terms                   Purpose
          ------              ----------                                ------              -----                   -------
                                                                                                     
          Ameren Corp.        Ameren  Energy Marketing                   $  1,000,000        04/03/03-05/31/04     Credit Support
          Ameren Corp.        Ameren  Energy Resources Generating Co.    $  3,000,000        05/27/03-12/31/04     Credit Support
          Ameren Corp.        CILCORP Energy Services Inc.               $  5,000,000        05/05/03-12/31/03     Credit Support
          Ameren Corp.        Ameren  Energy Marketing                   $  1,000,000        06/26/03-12/31/04     Credit Support
          Ameren Corp.        CILCORP Energy Services Inc.               $  5,000,000        05/05/03-12/31/04     Credit Support
          Ameren Corp.        Ameren  Energy Fuels & Services Co.        $    500,000        05/15/03-12/31/03     Credit Support
          Ameren Corp.        Ameren  Energy Marketing                   $  7,500,000        06/17/03-             Credit Support



     7.   The name and amount  invested  by Ameren in any  Financing  Subsidiary
          during the calendar quarter.

          N/A


     8.   The notional  amount and principal terms of any Interest Rate Hedge or
          Anticipatory  Hedge  entered into by Ameren during the quarter and the
          identity of the parties to such instruments.

          No such agreements were entered into during the 2nd quarter of 2003.


     9.   Consolidated  balance  sheet of Ameren  as of the end of the  calendar
          quarter.

          Incorporated  by reference  to  Quarterly  Report on Form 10-Q for the
          quarterly period ended June 30, 2003 in File No. 1-1756.


B.   Financing by CILCORP and Utility Subsidiaries
     ---------------------------------------------
    (File Nos. 70-10106 and 70-10078):

     1.   The type of long-term securities (e.g., common stock,  long-term debt,
          preferred   securities,   etc.)  issued  by  CILCORP  or  AmerenEnergy
          Resources  Generating Company (AERG) f/k/a Central Illinois Generation
          Inc.  (CIGI)  during  the  quarter  and the  amount  of  consideration
          received.

          No such securities were issued during the 2nd quarter of 2003.


     2.   The principal  terms (e.g.,  interest rate,  maturity,  dividend rate,
          sinking fund provisions,  etc.) of any long-term  securities issued by
          CILCORP or AERG during the quarter.

          N/A

                                       2




     3.   The  amount  and  terms of any  Short-term  Debt  issued  by  CILCORP,
          AmerenUE,  AmernCIPS,  AmerenCILCO  or AERG  (other  than  through the
          Utility Money Pool) during the calendar quarter.

          AmerenUE  issued  commercial  paper  during  the 2nd  quarter  of 2003
          through A. G. Edwards, Goldman Sachs, and/or Bank One Capital Markets,
          ranging up to $177.1 million,  at an average interest rate of 1.3%. No
          Short-Term Debt was issued by the other identified entities during the
          2nd quarter of 2003 (other than through the Utility Money Pool).

          There were no bank loans for the 2nd quarter of 2003.

          Maximum indebtedness at any one time: $177.1 million on 6/30/03.


     4.   If payment of any debt  securities  may be  accelerated by the holders
          thereof by reason of a default by any associate  company of the issuer
          under  any  obligation  of  such  associate  company  (i.e.,  a  cross
          default),  the  identity of such  associate  company and the nature of
          obligation  of the  associate  company  to  which  the  cross  default
          relates.

          There exists a cross default  provision in the  indenture  relating to
          CILCORP's 8.70% and 9.375% senior unsecured notes, whereby an event of
          default would be triggered if there is a default in the payment of the
          principal  under any  mortgage,  indenture or  instrument  under which
          there may be issued or by which there may be secured or evidenced  any
          indebtedness for borrowed money of any significant subsidiary. Default
          must be for an aggregate  amount  exceeding  $25  million.  This would
          apply  to  any   outstanding   short-term  or  long-term   AmerenCILCO
          indebtedness, including funded bank loans.


     5.   The amount and purpose of any Guarantee issued by CILCORP.




          Parent              Subsidiary                                Amount              Terms                   Purpose
          ------              ----------                                ------              -----                   -------
                                                                                                     
          CILCORP, Inc.       CILCORP Energy Services, Inc.             $2,000,000          01/01/03-12/31/03     Credit Support

          Beneficiaries - Tenaska Marketing Ventures, Tenaska Marketing Canada, Tenaska Gas Storage, LLC




     6.   The notional  amount and principal terms of any Interest Rate Hedge or
          Anticipatory  Hedge  entered  into  during  the  quarter  by  CILCORP,
          AmerenUE,  AmerenCIPS,  AmerenCILCO  or AERG and the  identity  of the
          parties to such instruments.

          No such agreements were entered into during the 2nd quarter of 2003.


     7.   With  respect to each  Financing  Subsidiary  that has been  formed by
          CILCORP,  AmerenCILCO  or AERG, a  representation  that the  financial
          statements  of the parent  company of the Financing  Subsidiary  shall
          account for the  Financing  Subsidiary in  accordance  with  generally
          accepted accounting  principles and further, with respect to each such
          entity,  (i) the name of the  Financing  Subsidiary,  (ii) the  amount
          invested by the parent company in such Financing Subsidiary; (iii) the
          balance  sheet  account  where  the  investment  and  the  cost of the
          investment  are  booked;  (iv) the  form of  organization  (e.g.,  ---
          corporation,  limited  partnership,  trust,  etc.)  of such  Financing
          Subsidiary;  (v) the percentage owned by the parent company;  and (vi)
          if any equity  interests  in the  Financing  Subsidiary  are sold in a
          non-public offering, the identity of the purchasers.

          N/A

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     8.   Consolidated   balance  sheets  of  AmerenUE,   AmerenCIPS,   CILCORP,
          AmerenCILCO and AERG as of the end of the calendar quarter,  which may
          be  incorporated  by reference to filings,  if any, by such  companies
          under the Securities Act of 1933 or Securities Exchange Act of 1934.

          Incorporated  by reference to the  Quarterly  Reports on Form 10-Q for
          the  quarterly  period  ended  June 30,  2003  filed by the  following
          companies: AmerenUE in File No. 1-2967, AmerenCIPS in File No. 1-3672,
          CILCORP in File No. 2-95569,  and AmerenCILCO in File No. 1-2732. AERG
          will not become operational until AmerenCILCO's  generating assets are
          transferred to it which is currently scheduled to occur later in 2003.
          Consequently,  AERG's  balance  sheet is not being  provided with this
          report.


C.   Money Pool Transactions (File No. 70-10106):
     -----------------------

     1.   The maximum outstanding amount of all borrowings from and loans to the
          Utility Money Pool by each Utility Money Pool  participant  during the
          quarter,  and the rate or range of rates charged on Utility Money Pool
          borrowings  and paid on  Utility  Money  Pool  investments  during the
          quarter.

          Maximum contribution/investment for AmerenCIPS - $27.3 million
          Maximum contribution/investment for AmerenUE - $0.0
          Maximum contribution/investment for Ameren Corporation - $394.2
            million

          Maximum borrowing for Ameren Services - $79.8 million
          Maximum borrowing for AmerenUE - $324.9 million
          Maximum borrowing for AmerenCIPS - $63.0
          AmerenCILCO's participation in the Utility Money Pool is subject to
            the SEC's release of its jurisdiction which is currently pending.
            The Illinois Commerce Commission, by order dated July 9, 2003,
            approved AmerenCILCO's particiation in the Utility Money Pool.

          Average interest rate for the Utility Money Pool for the quarter: 1.2%


     2.   The maximum outstanding amount of all borrowings from and loans to the
          Non-Regulated  Subsidiary Money Pool by each Non-Regulated  Subsidiary
          Money Pool  participant  during the quarter,  and the rate or range of
          rates charged on  Non-Regulated  Subsidiary  Money Pool borrowings and
          paid on Non-Regulated  Subsidiary  Money Pool  investments  during the
          quarter.

          Maximum contribution/investment for Ameren Corporation - $414.4
            million

          Maximum borrowing for Ameren Energy Fuels and Services - $22.5 million
          Maximum borrowing for Ameren Development - $1.5 million
          Maximum borrowing for Ameren Energy Communications - $29.3 million
          Maximum borrowing for Ameren Energy Development - $28.2 million
          Maximum borrowing for Ameren Energy Generating - $233.3 million
          Maximum borrowing for Ameren Energy Resources - $36.2 million
          Maximum borrowing for Ameren Energy - $12.1 million
          Maximum borrowing for CIPSCO Investment Co. - $7.7 million
          Maximum borrowing for Ameren ERC - $15.9 million
          Maximum borrowing for Illinois Materials Supply - $5.2 million
          Maximum borrowing for Ameren Energy Marketing - $24.4 million
          Maximum borrowing for Union Electric Development - $2.6 million
          Maximum borrowing for Ameren Services - $.2 million

          Average interest rate for the Non-Regulated Subsidiary Money Pool for
            the quarter: 8.8%

                                       4




D.   Other  Transactions  Involving Ameren's  Nonutility  Subsidiaries
     -----------------------------------------------------------------
     (File No. 70-9427):

     1.   Balance Sheet and Income  Statement for each  Intermediate  Subsidiary
          for the three, six or nine month period ended.

          To be filed confidentially under Rule 104.


     2.   Information  concerning the nature and extent of services  provided by
          any Nonutility  Subsidiary  that is authorized or permitted  under the
          Act to sell goods and  services  during the quarter,  identifying  the
          associate company to which such services are sold, the service and the
          charge, and stating whether the charge was computed at cost, market or
          by another method (as specified herein).

          To be filed confidentially under Rule 104.


     3.   Information   concerning  the  completion  of  any  reorganization  of
          Ameren's  ownership in  Intermediate  Subsidiaries  and/or  Nonutility
          Subsidiaries,  including  the identity of the  companies  involved and
          their line of business and corporate  structure  both before and after
          the reorganization.

          N/A


     The undersigned  registered  holding company has duly caused this quarterly
report to be signed on its  behalf by the  undersigned  officer  thereunto  duly
authorized  pursuant to the  requirements  of the Public Utility Holding Company
Act of 1935.

Ameren Corporation




By          /s/ Jerre E. Birdsong                          Date: August 29, 2003
  ---------------------------------------------
                Jerre E. Birdsong
                Vice President and Treasurer






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